The independent variable is either a cause or a predictor, depending on the research design.
A dependent variable is the outcome researchers intend to produce, modify, or predict.
Extraneous variables are those not central to a study’s research purpose but have a potential effect on the results, making the independent variable appear more or less powerful than it really is in its effect on the value of the dependent variable.
Confounding variables are the extraneous variables that are not recognized until the study is in process or that are recognized before the study is initiated.
A research variable is a default term used to refer to a variable that is the focus of a quantitative study but that is not identified as an independent or a dependent variable.
Modifying variable is a variable that changes the strength, and possibly the direction, of a relationship between other variables.
Mediating variable is a variable that is an intermediate link in the relationship between other variables.
Environmental variable is a characteristic of the study setting.
A conceptual definition identifies the meaning of an idea.
The researcher selects the operational definition that results in a measurement of the dependent or research variable that is best for that study.
Theory is an abstract generalization that explains how phenomena are interrelated.
Grand theories or macro-theories purport to describe and explain large segments of the human experience.
Middle-range theories tend to involve fewer concepts or propositions, are more specific, and are more amenable to empirical testing.
Practice theory are highly specific, narrow in scope, and have an action orientation.
Conceptual models, conceptual frameworks, or conceptual schemes provide a perspective regarding interrelated phenomena but are more loosely structured than theories.
Schematic models (or conceptual maps) are visual representations of some aspect of reality.
A visual or symbolic representation of a theory or conceptual framework often helps to express abstract ideas in a concise and accessible form.
Framework is the overall conceptual underpinnings of a study.
The concepts central to models (NEHH) of nursing are human beings, environment, health, and nursing.
Two major conceptual models of nursing used by researchers are Roy’s Adaptation Model and Rogers’ Science of Unitary Human Beings.
Non-nursing models used by nurse researchers (e.g., Bandura’s Social Cognitive Theory) are borrowed theories; when the appropriateness of borrowed theories for nursing inquiry is confirmed, the theories become shared theories.
Some qualitative researchers specifically seek to develop grounded theories, data driven explanations to account for phenomena under study through inductive processes.
Cross-sectional designs involve the collection of data once the phenomena under study are captured at a single time point.
Longitudinal Designs is a study in which researchers collect data at more than one point in time over an extended period.
Reliability refers to the accuracy and consistency of information obtained in a study.
Validity is a more complex concept that broadly concerns the soundness of the study’s evidence—that is, whether the findings are cogent, convincing, and well grounded.
Trustworthiness in qualitative research encompasses several different dimensions, including dependability, confirmability, authenticity, transferability, and credibility.
Credibility is achieved to the extent that the research methods engender confidence in the truth of the data and in the researchers’ interpretations.
Triangulation, the use of multiple sources or referents to draw conclusions about what constitutes the truth, is one approach to establishing credibility.
A bias is an influence that distorts study results.
Systematic bias results when a bias operates in a consistent direction.
In quantitative studies, a powerful tool to eliminate bias is randomness; having certain features of the study established by chance rather than by personal preference.
Generalizability in a quantitative study concerns the extent to which findings can be applied to other groups and settings.
Transferability is the extent to which qualitative findings can be transferred to other settings.
Control group refers to a group of participants whose performance on an outcome is used to evaluate the performance of the treatment group on the same outcome.
A placebo or pseudo-intervention presumed to have no therapeutic value.
Randomization (also called random assignment or random allocation) involves assigning participants to treatment conditions at random.
A procedure called blinding (or masking) is often used in RCTs to prevent biases stemming from awareness.
Quasi-experiments, often called controlled trials without randomization in the medical literature, involve an intervention but they lack randomization, the signature of a true experiment.
The signature of a retrospective study is that the researcher begins with the dependent variable (the effect) and then examines whether it is correlated with one or more previously occurring independent variables (potential causes).